Inductance system



ug. 4, 1931. L. A. GERHARD. l 1,817,247

INDUCTANGE SYSTEM ATTORNEY Aug. 4, 1931.

L. A. GEBHARD 1,817,247

INDUCTANGE SYSTEM i Filed June 5. 1929 2 sheetysneez 2 -ln E- E JNVENToR.

A TTORNEY 'i Patented u. 4, 1931 UNITED STATES PATENT OFFICE LOUIS A. GERHARD, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR T WIRED RADIO, INC., OF NEW YORK, N. Y., A

CORPORATION OF DELAWARE INDUCTANCE SYSTEM Application led lune 5,

My invention relates broadly to frequency chan 'ng systems, and more particularly to iniictance systems employed in frequency changing4 systems.

5 One of the objects of my invention is to rovide an eicient and easily manipulated inductance system for high frequency transmission systems.

Another object of m invention is to ro- 1o vide an eiiicient arti c ially cooled in uctance system for high frequency transmission systems.

Still another object of my invention is to provide in a high frequency signaling sysr, tem, an inductance arrangement in which a circulating liquid cooling medium is employed for maintaining the inductance arrangement at normal temperatures.

A further object of my invention is to provide an artificially cooled inductance system having a plurality of inductance units associated therewith in which connections between each of the inductance units and a reservoir of circulating cooling medium are provided for the inductance units substantially at or near the electrical centers there- A still further object of my invention is to provide an artificially cooled inductance system having a Jplurality of inductance units made up o concentrically disposed coiled tubes in which connections between the tubes of each of the `inductance units and a reservoir of circulating cooling medium are provided for the inductance units substantially at or near the electrical centers thereof.

Other and further objects and features of my invention will be a parent to those skilled inthe art to whic this invention relates from the following specification and the appended drawings.

It is an object of my invention to provide 'a tube, disposed within the main or outer tube of the inductance, for ther iiow in 1929. Serial No. 368,692. gi,

one direction of the circulating cooling medium and to provide connections of preferably flexible tubing material, such as rubber tubing, for the inner tube and the outer tube of the'inductance unit at places on the inductance where the magnitude of the high frequency voltage is a very low or minimum value. l/Vhero the inductance system of my invention is employed in a balanced or push pull electron discharge `device circuit arrangement the place of minimum or substantially minimum magnitude of high frequency voltage is normally at or near the center of the inductance unit.

According to my invention an inductance system adapted for artificial cooling through the action of a circulating cooling medium is provided with a plurality of inductance units each made up of coiled tubes through which the circulating cooling medium is passed. ing certain of the inductauce units into the circuits of a signaling system when certain operating conditions are to be attained and other inductance units when other operating conditions are desired. Flexible connections, made of material such as rubber tubing, are provided between the inductance units and the cooling medium reservoir. Ordinarily rubber tubing is not a very good insulator for high frequency currents. It is therefore undesirable to connect the rubber tubing to an inductance unit, employed in a signaling system, at a place on the unit where a high frequency voltage of substantial magnitude exists. It is furthermore impractical to. connect the rubber tubing to points on the inductance unit where high frequency because the liquid cooling medium, such as water, which is usually employed, while being a good insulator -when pure is usually a good conductor when impure. Where impurities, such as dissolved metal salts, pieces of carbonized rubber and the like,

Provision is also made for connectvoltages of large magnitude exist are present in the liquid cooling medium, the cooling medium becomes a fairly good conductor and the rubber tubing connections to the inductance unit introduce additional losses -into the circuit.

Referring to the drawings, Figure 1 illustrates an embodiment of my invention; Fig. 2 is a cross-sectional view along line 2 2 of Fig. 1; Fig. 3 is a detail view in broken cross-section of an inductance unit embodying my invention; Fig. 4 is a vieu7 in fragmentary section of the inductance unit and Fig. 5 is a cross-sectional View along line 5'-5 of Fig. 3.

In Fig. l reference numeral 1 designates a rotatable frame member having crosspieces 2, 3, 4 and 5 supported by end pieces 9 and 10 which are provided with radiating arms for engaging certain of the cross pieces. The rotatable frame member 1 is made of insulating material, such as, synthetic porcelain, Wax impregnated dried wood, or the like. A shaft G is centrally disposed between the end pieces 9 and 10 which are fixedly attached thereto. Upright members i' and 8 are positioned upon the panel 11 for supporting the shaft G in rotatable position. A handle 12 or similar member, such as a dial or knob which may be readily engaged by the hand of theV operator, is mounted upon the shaft 6. Inductance units 13,14, 15 and 1G comprising helically coiled metallic tubing are mounted upon the crosspieces 2, 3, 4.- and 5, respectively. A bar member 17 of insulating material, such as synthetic porcelain, wax impregated dried Wood or the like is supported adjacent to the frame member 1. Pairs of contact members 18, 19, 20 and 21 are positioned on the.

member 17 in spaced relation for engaging pairs ofcontacts 22, 23, 24 and 25 associated with the inductance units 13, 14, 15 and 16, respectively.

Rubber tubing connections 26 are provided between the inductance units and a coil of rubber tubing positioned about the shaft 6, as illustrated in Fig. 2. The cooling liquid is caused to pass through a portion of the coil of rubber tubing upon shaft 6 and then through the inductance units successively. By employing a coil of rubber tubing centrally positioned as to the frame 1 upon the shaft 6 the inductance system may be rotated and different inductance units connected into circuits of a signaling system with `minimum Wear upon the rubber tubing.

In Fig. 3 an end View of one of the'inductance units is illustrated in partial crosssection. kThe outer metallic tube 27, preferably of copper, encloses a metallic tube 29 of smaller diameter. vSpacer members 28 are soldered or otherwise aHiXed to the coiled tubing 29. A space is provided between the inner surface of tube 27 and the outer surface of tube 29 as illustrated in Fig. 5. A cap member 30 is' soldered or otherwise fixed to the end of tube 27. The surface of cap member 3() is smoothed to minimize the corona discharge taking place therefrom since the ends of the inductance unit are at a comparatively high radio frequency potential. Both ends ot' thein-:luctance units are provided with smooth cap members similar to cap 30 in imluctance .system employed in the balanced or push pull electron discharge device circuit arrangements. Irojccting tubes 3l and 32 'are soldered, welded or otherwise aiiixed to the coiled tubes 29 and 27, respectivelv, as illustrated in Fig. 4.

The. circulating cooling medium is caused to enter the tube Ill through a rubber tubing connection attached to this tube and flows through the coiled tube 2S). The cooling medimn discharges from the end oi' the tube 29 into the tube 2T and flows through the space between the tube 29 and the tube 2T. rilhe surfaces of the tube 27, which carries the major quantity of the high frequency current flowing through the inductance unit, are thus cooled.

vWhile. I have described a preferred embodiment of my invention I desire it understood that various modifications thereof may be made without departing from the spirit of my invention and therefore I do not desire to restrict my invention to the exact details set forth in the foregoing specification except in so far as these details are detined by the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In an inductance system the combina tion of an inductance unit. means for connecting a supply oi' circulating cooling medium to said inductance unit, said inductance unit comprising concentric helical tubes disposed one over the other.

2. In apparatus of the class described the combination of an inductance unit compris ing a plurality of concentric helical tubes disposed one over the other, said helical tubes being subject to uniform heatingv throughout their length by the passage of current therethrough. and means for connecting a supply of circulating cooling medium to each of said tubes.

3. In an inductance system the combination of an inductance unit comprising tubes disposed one within another, plug members positioned in the respective ends of the outer one of said tubes and spaced from the respective ends of the inner of said tubes, and means for connecting the electrical center of said tubes of said inductance unit and a supply of circulating cooling medium.

4. In an inductance system of the class described the combination of a plurality of inductance units each comprising a plurality of tubes disposed one within the' other, a rotatable frame whereon said inductance units are mounted about a common axis, and liquid conducting members for connecting a supply of circulating coolin medium to said inductance units, said liqui conducting members being positioned substantially along said common axis.

5. In an inductance systemy for currents of radio frequency the combination of a plurality of inductance units each comprising a plurality of tubes disposed one within the other, and means for connecting a supply of circulating cooling medium to each of said tubes at places of low operating radio frequency potential. r

6. In an inductance system` of the class described the combination of a plurality of inductance units, a rotatable frame member for supporting said inductance units, each of said inductance units comprising a plurality of tubes disposed one Within the other, and means for connecting a supply of circulating cooling medium to said inductance units, said inductance units having contacts for engaging stationary contacts supported adjacent to said frame member.

7. In an inductance system for radio frequency-currents, a plurality of inductance units each comprising a pair of concentric tubes one surrounding the other, a rotatable frame having lateral members Whereon lsaid inductance units are symmetrically mounted about a common axis, plug members closing each end of the outer tube of each of said inductance units, each end of the innerY tube 'of each of said inductance units being open andspaced from its re spective adjacent plug, members connected to ,intermediate points of each of said inductance units for conducting cooling liquid to 'one of said tubes and away from the other of said tubes, said inductance units being electrically insulated from each other, and means for selectively connecting each of said inductance units with an external circuit.

8. In an inductance system for radio requency currents, a plurality of inductance units each comprising a pair of concentric tubes one surrounding the other, a rotatable frame having lateral members Whereon said inductance units are symmetrically mounted about a common axis, plug members closing each end of the outer tube of each of said inductance units, each end of the inner tube of each of said inductance units being open and spaced ,from its respective adjacent plug, liquid cpnducting members connnected to intermediate points of each of said inductance units for conducting cooling liquid to one of said tubes and away from the other of said tubes, being electrically insulated from each other, and means for selectively connecting each liquid conducting said inductance units inductance units are symmetrically mounted about a common axis, plug ing each end of the outer tube of each of said inductance units, each end of the inner tube of each of said inductance units being open and spaced from its respective adjacent plug, liquid conducting members connected to each of said inductance units substantially at the mid-point thereof for conducting cooling liquid to one of said tubes and away from the other of said tubes, said inductance units being electrically insulated from each other, and means for selectively connecting each of said inductance units with an external circuit.

10. In an inductance system for radio frequency currents, a plurality of inductance units each comprising a pair of concentric tubes one surrounding the other, a rotatable frame having lateral members Whereon said inductance units are symmetrically' mounted about a common axis, plug members closing each end of the outer tube of each of said inductance units, each end of the inner tube of each of said inductance units being open and spaced from its respective adjacent plug, liquid conducting members connected to each of said inductance units substantially at the point of minimum radio frequency ducting cooling liquid to one of said tubes and vaway from the other of said tubes, said inductance units being electrically insulated from each other, and means for selectively connecting each of said inductance units with an external circuit.

11. In an inductance systemfor radio frequency currents, a plurality of inductance units having each comprising a pair of concentric tubes one surrounding the other, a rotatable frame having lateral members Whereon said inmembers closductance units are symmetrically mountedbeing electrically insulated from each other,

and means for selectively connecting each potential thereof `for con-` ioo different values of inductance 4 mima of said inductance units with an external circuit. A

12. In an inductance system, a pair of concentric tubular members one surrounding 5 the other, and inlet and outlet ow connections for said tubular members substantially at the points of minimum potential thereof, said tubular members bem provided With How-controlling stops w ereby cooling liquid delivered to said inlet connection flows continuously through said tubular members to said outlet connection.

LOUIS A. GEBHARD. 

